This is probably the least detailed of the Articles of Faith, and yet it covers some of the most important doctrinal principles and aspects of God's plan for our happiness and progress.  It begins with agency.  Agency is the ability to choose how we will think and act.  It is so important to our Heavenly Father and his plan that there was war in heaven over it.  Satan thought he had a better plan - to force everyone to be good.  However, a man cannot show that he is good if he is forced.  Goodness must be chosen.  Satan persuaded a third of God's children to support him in direct opposition to God.  God honored their agency and did not force them to come to earth and receive physical bodies and all of the blessings that come from the mortal experience.  They were cast out of heaven and continue their war with God's children here on earth.

In order for agency to exist, there must be opposing choices and attached consequences.  God gives us commandments that, if followed, will bring freedom, progress and happiness.  Satan entices us, through the lusts of the flesh, to disobey those commandments.  When we choose to disobey, it brings sorrow and bondage and hinders our progress.  We are taught by parents, prophets and other church leaders and scripture so that we know right from wrong and can choose for ourselves.  We then become responsible or accountable for the choices we make and the consequences that follow.

Mortality is a probationary state in which we prepare for immortality.  We are faced on a daily basis with the opportunity to make choices and experience their consequences.  In the process, we learn and prove whether or not we will be obedient and choose happiness and eternal life.

When Adam partook of the forbidden fruit, Satan encouraged him to hide rather than take responsibility for his choice.  When we likewise make wrong choices, Satan tempts us to hide our mistakes out of fear and shame, but God's desire is that we turn to him and repent so that we can grow and be healed (1).  It is through the atonement of Christ that we can be forgiven.

Much of the Christian world believes that little children are conceived and born in sin, but Moroni teaches us that because of the atonement, little children are alive in Christ.  They make mistakes and are taught and corrected by parents and teachers and learn in the process.  They are not accountable until they are eight years old and are capable of understanding and commiting sin.  Adam's transgression brought mortality, but it did not make us evil from birth.  It is our choices and how we respond to those choices that will determine our eternal destiny.

1  Don't Miss This by David Butler and Emily Belle Freeman, Genesis 3-4, Moses 4-5.

(For additional insights, read The Articles of Faith by James E. Talmage.  Also listen to Don't Miss This, Old Testament on YouTube by David Butler and Emily Belle Freeman.)